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' C 1,626,762 May 1927. P.- L SCOTT l.

RELIEF BIECHANISM FOR FUEL INJECTION SYSTETIS K' Original Filed Jan. y1.8. `1918 zflforzzeyp' y Patenfd' Mas/3, 1927,.

`UNITEo.sTA y rHIL'IP LANEsoornr,y OF OH'IOAGo, IfLL-INOIsA'ssIGNoR :ro ysur'iinnIEsEL frmio'ron CORPORATION, ordina` PORTE, INDI'ANn` A oonronivr10N"'oF NEW YORK.

i, f namur" yivmorIANrsM' non rUEL-'rNJEoTION sYs'rnivrs.`

'Continuation of application Serial ,This application isfa continuation offmyl application filed 'on yJanuary 18, 1918 under' temperature of a charge of air that haspre# viously loeenffadmitted` to the cylinder and l `compressed to a high degree during the compump stroke'`a`nd the amount of fuelr der pression fst'rokeof the engine: '.The" liquid fuelk'is supplied to the cylinder through a sprajT valve'and with thetypes of :pumps at ypresent inuse" the rateof injection' "ofthe ffuel decreases rapidly toward the end of the klivered is so`^small that there is atendency for drops tof Oozel out at thevfend'of the pumping strokedue tov residual pressure in the pumpohamber; Th'ese'drops maj7 eithery vlo'urn at the endfof'the injection periodjust Voompleted ormavremain onk the nozzle un- 'tilth'enext injectionperiod when theywill 'be ycarried forward asdrops with the new yfuel ChargeA In either'case there is *com-y i an-arrarigement such tha'tlthe plunger will.

loustion in the` relative liquid from these ',drops. f f j i l y'It is object of the present invention to provide, yin connectionl with. ythe' `mechanism 'for operatin'gtlie pump plunger or piston,

he disengaged fromits actuating mechanism r yasit approaches the'jlimit loi'its working'v stroke,y and quickly returned to the'position yit occupies at the'beginningjofthe: stroke. This quick 'release of the pump plungerwill cause a sudden diminutionof pressurein 1v 'l 'Referring 'to thedrawingskinl whiclig f, l'Figure lis "1' Figure '2'isf a plan view With a portion f HVVot thehousingfA of the lmechanismbroken" i through .the roller 18'and eap'17 will cause the pump'plunger12 tomakeAv its working 1 401'" the passage Way'leading4 to the valve and in the' pump chamber' whichk controls the admission lo'l, fuel to they cylinder, and this valve'fwill close suddenly due to this reduc.-

'tion' in pressuretocut ofi' the fuel andfprei vent it from dripping into the cylinder.

r The particular@natureI of the presentinvention willfappearl more clearly fro'rnl'a description of ya' preferred embodiment there- ,of as shown y'in'k theaccompanying drawing inwhich:

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an"v elevation chieiy section,z'

'flatter willrmakefa rolling contact with the similar reference characters denotek similar ipartsin each of the tigures,` designates the casing or hodvo'f. a fuel'pump which may be of anyvpreferred construction. Attached tothe pumpcasing 1s a housing 11 which carries the mechanlsm of the present invention. flhe'portion of the `housing` adjacentthe pump casing isrprovided with .a loore` within'wliich extends the outer end of the pump plunger 12, the latter .being provided with an enlarged end 13 surrounded by a head 14 r,which forms an abutment for' one end ot thespring 15,1 the otherf'end of which `is placed around-a post ,16 projecting from .the end; ot the pump scasing. A guiding` cap 17 is slidahlymounted in the bore of the housing 11 and engages the end of the pump plunger. "A roller 18 contactsvwith n the end of the cap-17, and lthis roller is `mounted on. a lever vv1`9'i'vhieh is` pivoted to ai shaft `2O supported in heaiungsy 2'1"V projecting from the inner Wallsoty the housing.

Anwarmf22 withinv the housing is provided With arolling surfacejadapted to en gage the outer edge of lever 19, and this army 22 isr attached to a shaft 23y mounted in One end ofy shaft This 'application mcd/August y15, f

.hearings v24 projecting `from the inside of l the'walls of the housing.

23 is extended through the housing, and to this end is attached an arm 25ghaving a Aforked upper endl 26 to receive rod 27'which 'is connected .1n any desired manner tol a kpart of the engine adaptedtol reeiprocatetlns rod. -A plate 28, :preferablv formed ofl hardenedsteeh is attached `to the lower face v4lof rod 27,'. and normally, makes Contact with the upper edge of arm 25. The lower face yofthe arm 27 is provided with-an inclined or cam face 28 adapted when the rod 27 is A movedftoward the pump to engage the nose of a set screw 30 mounted in ak bracket 31 formed on thefoutside of thehousing e The operation of themechanism kdescriloed above is as follows :k

The yrod 27 is reciprocated from a moving y'parte of theI engine,"-and,= assuming that it starts from the position :shown in Fig.r ,1, with theplate 28 engaging 'the-upper end 'of arm l25, this arm willrbe rotated andvlike-k wise thearm 22."Thercurvedface ofthe lever` 19 'moving the latter inwardly and stroke. As soon, however, as the cam face 29 engages the nose of set screw 30, the rod 27 will be lifted suiiiciently to release plate 28 from the upper end of the arm 25, but the rod will be retained in place within the forked end of this arm. As soon as the actuating rod 2T has been disengaged from the arm 25, the spring l5 which was put under compression during the working stroke of the pump will quickly restore the pump plunger, lever 19 and arms Q2 and 25 to their outward position, thus causing a sudden release of the pressure in the pump chamber. This sudden release of pressure will permit a quick closure of the valve controlling the admission of fuel into the engine cylinder to cut ofi' the fuel and prevent it from dripping into the cylinder. As soon as the reciprocating rod has been moved ontwardly far enough for the plate 2S to again engage the upper end of the arm 25, the mechanism will be restored to condition for a subsequent operation.

Some pumps of the general type used for injecting liquid fuel into the c vlinder of an internal combustion engine under high pressure are provided with a discharge valve communicating with the pump chamber and through which the fuel passes before going to the passageway leading to the spray valve, but with the quick relief mechanism of the present invention, the sudden diminution of pressure in the pump chamber caused by the quick release of the pump plunger would canse the discharge valve to close immediatelyr thereby preventing the diminution of pressure from extending to the spray valve and defeating the purposeof this invention. This defect may be avoided by removing the discharge valve from the fuel pump and allowing` the spray valve to control the admission of fuel from the pump enamber to the engine cylinder' or any suitable construction may be provided for holding the discharge valve open at the instant when the pressure in the system is to be relieved.

It will also be understood that various changes in the details of construction may be made without departing from the principle of the invention.

I have spoken of the sudden release of pressure in the fuel line which permits a quick closure of the valve controlling admission of the fuel and prevents the formation of drops at the spray valve. This sudden pressure release which is due to the sudden withdrawal of the pump plunger sets up a negative pressure at all parts in the injection system between the injection valve and the spray valve. If the drives are positive mechanical drives with all members at all times joined to permit motion in either direction, the return movement of the pump plunger would accomplish solid pressure release in the system before drops have a chance to form due to the residual pressure from the injection stroke just preceding, that is, all eccentric or cam forms normally used prevent a sudden pressure release due to the inability to get sufficient high acceleration in the reverse direction without straining the mechanism.

If, however. some member' of the driving linkage can be suddenly thrown out of operation, that is if the drive is not an opposite drive in both directions, such member can be disconnected and at the instant of its disconnection if a spring opposed to the oj'ieration of the driving` linkage, this spring will impart to the pump plunger very rapid acceleration in the opposite direction to its pumping` stroke producing a very sudden diminution in the injection pressure, so sudden that drops will not have time to form.

I claim:

l. In a pump for supplying fuel to the combustion chamber of an internal combustion engine. a pump plunger, a lever for actuating'said plunger, an arm engaging said lever. a second arm associated with the first arm, a reciprocating rod actuated by the moving parts of the engine and normally engaging said second arm to rotate the arm and through the first arm and lever actuate the pump plunger, means for disengaging said rod from said second arm as the pump plunger approaches the end of its working stroke and a spring for quickly with-draw ing said plunger to relieve the injection pressure when said rod is disengaged from said second arm.

2. In a pump .supplying fuel to the combustion chamber of an internal combustion engine. a pump plunger, a lever 'for actnat ing said j ilunger, an arm enga-ging the lever, a second arm operatively connected to said first arm, a reciprocating rod actuated by the moving parts of the engine and normally engaging the end of said second arm and adapted through said second arm, said first arm and said lever to cause the pump plunger to effect a working stroke, said rod being provided with a cam face, a .set screw adapted to co-act with the cam face of the rod to lift the rod out of engagement with said second arm` said set screw and Cam face being so related that the rod is disengaged from the second arm when the pump plunger' approaches the end of its working stroke. and means vfor quickly withdrawing said plunger to relieve the injection pressure when sai-d rod is lifted out of engagement with said second arm.

3. In a pump for. supplying fuel to the combustion chamber of an internal combustion engine, a pump plunger adapted to reciprocate in the chamber of the pump, a spring for normally withdrawing the plunger from the pump chamber, a slidable y witha slotted extremity, a reciprocating'rod ofthe plunger, a lever 'provided with ay roller adapted to engage the slidable meni-A ber, an arm provided withy a curvedr `face adapted to `engage an edge` of the lever, a Shaft to which said arinis attached, a second arm attached to "said shaft and rprovided within said extremity and having a plate of hardened material adapted to engage the upper end of .said arm, so that when said rod is actuated'by anioving partei the engine, it will through said arms, lever, and slidable vrmember compress said spring and cause said` lunofer to make a workin@ stroke, 'said reciprocating rod ybeing lprovide with a cani, surface on its under face', and a set screw f adapted to he engaged yby the cain face on saidrrod` at' the lend yof the pump .stroke to vlift the rod and disengage the plate" 'from the end of said` second arm to permit said sprin,`gfv to force thepuinp outward vto cause a sudden release offpressui'e' inV the pump chamber and fuel passages communicating therewith, substantially as described.

4-111 a pumpy for supplying-fuel tothe lcombustion chamber of an internal combustion engine, a pump plunger, a lever tu'iiifpressure.

Aadjacent toy the klever for swinging the saine, a reciprocatiiigrodactuated by the moving parts of the engine and normally engaging [said means to move the saine and swing the lever', means for vdisengaging the rod from said meansasthe pump plunger approaches the end of its working stroke, andi-means for quickly withdrawing they plunger to reliev'efthe injection pressure when the rod is disengaged from the means.

5. In a pump'ior .supplying fuel tothe bustioii engine, a pump plunger, a spring arranged to niovethe plunger on its suction stroke, mechanism for moving the plunger on the injection .stroke against the action of `40 coliibiistion Chamber of an` internal cointhe spring,*comprising a lever and a recipc "rocatinggrod actuated by rthe moving partsr` f "of the engine and operatively connected rto the `lever during this strokeyaiid means for swinging the rod out yof operative relation to -the ylever near Lthe end of the injectiony vstroke to permit the springy suddenly to withdraw the plunger and relieve the injec- Signed at Chicago county ofCook n State of Illinois,l this 13th day of August, f 192.1. v for actuating ,the plunger, means `mounted PiiiiiiP LANE SCOTT.y 

